Sutures are fibrous joints connecting the bones of the head. Despite the fundamental role played by sutures in dentofacial orthopaedics, their biomechanical properties are not completely understood. This study evaluated anatomy, biomechanics, and acoustic emission (AE) during distraction of the sutural ligament (SL).

Seventy-two suture samples were removed from a twelve-months-old swine (Sus scrofa) head. Each volume was acquired using micro-computed tomography (μCT), and the linear interdigitation index was calculated on both planes (LII_COR and LII_SAG). Mechanical testing till failure was carried at 1 mm/min, and four piezoelectric sensors were used for recording of amplitude (A), duration (D), and energy (E) of AE. The relationships between interdigitation, fracture types, tensile stress (σ₀), and AE were statistically analysed with non-parametric tests (α = 0.05).

σ₀ of the SL had median values of 4.0 MPa, and AE were characterised by A of 49.3 dB (IQR = 2.2), D of 826.3 μs (IQR = 533.4), and E of 57,715.8 eu (IQR = 439,613.5). Most of the fractures happened in the SL (46%), some within the bone (34%), and fewer were combined (19%). LII_COR had correlation with A (0.383, p = 0.028), D (0.348, p = 0.048), and E (0.437, p = 0.011) of the AE, and σ₀ had similar relationship with A (0.500, p = 0.003), D (0.495, p = 0.003), and E (0.579, p < 0.001). Maximum energy values were different between fractures within the bone and within the SL (p = 0.021).

Biomechanical properties under tension of most of the sutures of the craniofacial skeleton were reported. AE provided information about the sequence of events during SL distraction, and had significant relationship with its mechanical properties. Further studies are necessary to confirm these preliminary findings, and to identify their relationship with biological processes and dentofacial treatments.